Windows which slide to open positions and doors, such as patio doors, which slide, are frequently furnished with locks to secure them when in closed position. However, when these closures are unlocked and partially open, there is no protection against further unauthorized opening from the outside.
This problem has been previously addressed by inventors as evidenced by the following U.S. Pat. Nos.:
______________________________________ 345,779 July 20, 1886 Gilman 887,690 May 12, 1908 Pearce 2,481,329 Sept. 6, 1949 Monat ______________________________________
The present invention is intended as an improvement over previous devices in the simplicity of the design and the ease of installation on existing windows and sliding doors by the average householder.
It is, therefore, an object of the present invention to provide a latch lock which can be readily installed on existing windows and doors and which is unobstrusive in appearance and simple to operate. It is a further object to provide a lock which may be installed out of reach of an intruder to prevent opening of a closure beyond the point established by the occupant.
Other objects and features of the invention will be apparent in the following description and claims in which the principles of the invention are set forth, together with details to enable a person skilled in the art to practice the invention.